1. Resistance to alteration by system errors. A user who files data expects that the contents of the files will not be changed by system errors in either hardware or software. Since such errors inevitably will occur from time to time, the prudent system manager maintains a system of protective dumps, organized in such a way that there always exists a valid copy of a recent version of every file on the system. For this to be possible, the manager must run system utilities that operate at such a level of privilege that they bypass the normal checks present to maintain the privacy and security of users’ files. The dump utilities must be able to read the users’ files in order to make copies, and must have write access to the users’ files in order to reinstate a recent version of a file lost or corrupted by system error. Thus the system for maintaining the integrity of a user’s files automatically constitutes a security vulnerability and represents a weakening of the system for maintaining privacy.

2. (safety integrity) The probability of a system always performing at some level of safety.